Method and machine for filling capsules or similar with at least two products, in particular pharmaceutical products in granules

ABSTRACT

The bottom shell of a capsule is filled with at least two products, contained in respective tanks, by means of a metering device, which has a metering chamber for receiving a given quantity of product from each tank; and a transfer chamber, which receives and transfers the product from the metering chamber to the bottom shell, and has a weighing device for weighing the product inside the transfer chamber.

The present invention relates to a machine for filling capsules or similar with at least two products.

More specifically, the present invention relates to a machine for filling capsules with pharmaceutical products in granules, to which the following description refers purely by way of example.

BACKGROUND OF THE INVENTION

In the pharmaceutical industry, a machine for filling capsules with pharmaceutical products in granules is known comprising a conveying device moving continuously along a given path and having a number of pockets, each for receiving a respective bottom shell of a capsule; two tanks of respective products; and a metering wheel mounted to rotate continuously about a substantially vertical longitudinal axis.

The metering wheel has a number of metering devices, each of which is moved by the metering wheel along a portion of the bottom shell path, in time with, and so as to transfer a given quantity of each product into, a respective bottom shell.

Each metering device comprises a substantially cylindrical metering chamber for receiving a given quantity of product from each tank; a feed chute for feeding the product from the metering chamber into the relative bottom shell; and a piston, which defines the bottom of the metering chamber, and moves along the metering chamber between an open position and a closed position opening and closing the feed chute respectively.

Because the second product is fed into the metering chamber after the first has been fed to the feed chute and the piston has moved back into the closed position, the product inside the metering chamber is weighed by a weighing device, in this case a capacitive transducer, fitted inside the metering chamber.

Starting with the metering chamber empty and the piston in the closed position, the operating sequence by which the product inside the metering chamber is weighed comprises the steps of:

lowering the piston to enable the weighing device to weigh the portion of the piston projecting inside the metering chamber;

raising the piston into a position corresponding to a given volume of the metering chamber;

filling the metering chamber with the product;

lowering the piston to enable the weighing device to measure the total weight of the piston portion projecting inside the metering chamber, and the product inside the metering chamber; and

lowering the piston into the open position to feed the product along the feed chute into the bottom shell.

The two weights are measured by moving the piston at constant speed from the same position along the metering chamber, so the weight of the piston portion projecting inside the metering chamber has exactly the same effect on both, and the weight of the product inside the metering chamber can be calculated as the difference between the two weights recorded by the weighing device.

Because the above operating sequence has to be performed twice—once for each product fed into the metering chamber—for each complete turn of the metering wheel about its longitudinal axis, and, each time, the piston has to perform a relatively large number of movements along the metering chamber, some merely to weigh the piston portion projecting inside the metering chamber, known machines of the above type have several drawbacks, mainly due to the relatively high travelling speed of the piston along the metering chamber, which jeopardizes not only correct filling of the metering chamber, but also correct weighing of the piston portion projecting inside the metering chamber, and each product inside the metering chamber.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a machine for filling capsules or similar with at least two products, designed to eliminate the above drawbacks.

According to the present invention, there is provided a machine for filling capsules or similar with at least two products, as claimed in Claims 1 to 13.

The present invention also relates to a method of filling capsules or similar with at least two products.

According to the present invention, there is provided a method of filling capsules or similar with at least two products, as claimed in Claims 14 to 20.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic view in perspective of a preferred embodiment of the machine according to the present invention;

FIG. 2 shows a schematic plan view, with parts removed for clarity, of a detail of the FIG. 1 machine;

FIG. 3 shows operating schematics of the FIG. 1 machine.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 3, number 1 indicates as a whole a machine for filling known capsules (not shown) with at least one pharmaceutical product in granules. Each capsule (not shown) comprises a substantially cup-shaped bottom shell 2, and a top shell (not shown) closing bottom shell 2.

Machine 1 comprises a metering wheel 3, in turn comprising a supporting shaft (not shown), which has a substantially vertical longitudinal axis 4, is fitted to a fixed frame 5 of machine 1, is rotated continuously about axis 4 and with respect to frame 5 by a known drive device (not shown), and supports a metering drum 6.

Drum 6 comprises a bottom disk 7, an intermediate disk 8, and a top disk 9, which are coaxial with and perpendicular to axis 4, and are connected in angularly fixed manner to one another and to the supporting shaft (not shown) to rotate about axis 4.

On the outer surface of disk 7 are formed: a sprocket 10 coaxial with axis 4 and forming part of a known conveying device 11 for feeding bottom shells 2 along a given path P; and an annular funnel 12 extending between sprocket 10 and disk 8, and tapering towards sprocket 10.

Device 11 comprises a chain conveyor 13 looped about a number of powered sprockets (of which only sprocket 10 is shown in FIG. 3) and comprising a number of substantially cup-shaped pockets 14, which are positioned with their concavities facing upwards, are equally spaced along conveyor 13, are each designed to house a respective bottom shell 2 with its concavity facing upwards, and are fed continuously by conveyor 13 along path P and beneath funnel 12.

In the example shown, frame 5 is fitted with two tubular containers 15, 16 (FIGS. 1 and 3 b), which are mounted on top of disk 9, are arranged about axis 4, each extend less than 180° about axis 4, are open at the top and bottom in a direction 17 parallel to axis 4, and each house a respective pharmaceutical product in granules.

Drum 6 comprises a number of metering devices 18 equally spaced about axis 4, and which are moved by drum 6 about axis 4 and along a portion of path P in time with respective pockets 14, so as each to withdraw a given amount of pharmaceutical product from each container 15, 16, and feed it into relative bottom shell 2.

Each device 18 comprises a substantially cylindrical metering chamber 19, which extends through top disk 9, has a longitudinal axis 20 parallel to axis 4, and is offset radially with respect to funnel 12; and a substantially cylindrical transfer chamber 21, which is formed through intermediate disk 8, has a longitudinal axis 22 parallel to axis 4, and is aligned in direction 17 with funnel 12.

Chamber 21 is bounded laterally by a bushing 23 fitted inside chamber 21, coaxially with axis 22, and comprising a capacitive transducer 24 integrated in bushing 23 and forming part of a weighing device 25 for weighing the product inside chamber 21.

Device 25 also comprises a known electric connector (not shown) coaxial with axis 4 and in turn comprising a fixed member fitted to frame 5, and a movable member fixed to drum 6 and connected electrically to capacitive transducers 24 of devices 18.

Bushing 23, capacitive transducer 24, and weighing device 25 are described and illustrated in the Applicant's Patent Application WO-2006/035285-A2, which is fully included in the present Application.

Chamber 19 is connected to chamber 21 by a feed chute 26 formed through disk 9, and is closed at the bottom by the top end of a piston 27, which is mounted coaxially with axis 20, extends through disks 7, 8 and 9, and is fitted in axially sliding, angularly fixed manner to drum 6 to slide, with respect to drum 6, straight along chamber 19 in direction 17.

Piston 27 has a changeable top portion 27 a, which is bounded at the top by a flat surface 28 sloping with respect to axis 20, is fitted removably to a bottom portion 27 b of piston 27, and can be changed according to the size of chamber 19.

As shown in FIG. 3 e, pistons 27 are moved along respective chambers 19 by an actuating device 29 comprising a known cam 30, and, for each piston 27, a respective cam follower roller 31 engaging cam 30.

Cam 30 extends about axis 4, and, at each container 15, 16, has a respective movable portion, which is movable in direction 17 independently of the other movable portion to selectively control the volume of chambers 19 at each container 15, 16.

Bach roller 31 is fitted in rolling manner to a top sleeve 32, which is fitted slidably to respective piston 27, is coaxial with relative axis 20, and is normally held contacting a top stop ring 33, fixed to piston 27, by a spring 34 fitted to piston 27, coaxially with axis 20, and interposed between sleeve 32 and a bottom sleeve 35 fixed to piston 27 and also coaxial with axis 20.

Chamber 21 is closed at the bottom by a shutter 36, which extends through disks 8 and 9 in direction 17, has a longitudinal axis 37 offset with respect to axis 22, projects from the top of disk 9 in direction 17, and is fitted td drum 6 to slide, with respect to drum 6 and straight in direction 17, between an open position (FIG. 3 a) opening chamber 21, and a closed position (FIG. 3 b) closing chamber 21.

Shutter 36 is normally held in the closed position by a spring 38 interposed between disk 9 and shutter 36, and is moved into the open position by its top end engaging a cam 39 fixed to frame 5 (FIG. 3 a).

Shutter 36 comprises a bottom portion 36 a made of insulating material with a low or zero dielectric constant; and a top portion 36 b made, for example, of metal.

Portion 36 a is substantially L-shaped and comprises a supporting rod 40, which slides inside a groove (not shown) formed through bushing 23 and parallel to direction 17, has a wedge-shaped portion 41 for dislodging any product clogging chamber 21, and, on its bottom free end, has a stopper plate 42 sloping with respect to axis 37.

Operation of machine 1 will now be described with reference to FIG. 3 and to one bottom shell 2 only, and as of the instant (FIG. 3 a) in which:

relative metering device 18 is located upstream from container 15 in the rotation direction of wheel 3 about axis 4;

relative shutter 36 is in the open position; and

relative piston 27 projects outwards of chamber 19 and cooperates with a suction device 43 for removing any product residue from chamber 19.

At this point, device 18 and relative bottom shell 2 are advanced in time with each other; piston 27 is lowered in direction 17 into a position closing chute 26 and corresponding to a given volume of chamber 19; shutter 36 is moved into the closed position to allow capacitive transducer 24 to weigh the portion of shutter 36 projecting inside chamber 21; and device 18 is fed beneath container 15 to allow a given quantity of the first product to drop by gravity into chamber 19 (FIG. 3 b).

Next, device 18 disengages container 15 (FIG. 3 c); and piston 27 is moved into position to open chute 26, so the product inside chamber 19 slides down chute 26 into chamber 21 (FIG. 3 d).

Finally, shutter 36 is moved into the open position, so the product in chamber 21 drops into bottom shell 2, and capacitive transducer 24 measures the total weight of the portion of shutter 36 projecting inside chamber 21, and the product inside chamber 21; and piston 27 is raised to close chute 26, project outwards of chamber 19, and cooperate with a second suction device 44 upstream from container 16 in the rotation direction of wheel 3 about axis 4 (FIG. 3 a).

Because the two weights are measured by moving shutter 36 at constant speed in direction 17 and between the same positions along axis 22, the weight of the portion of shutter 36 projecting inside chamber 21 affects both weight measurements in exactly the same way, so weighing device 25 can calculate the weight of the product inside chamber 21 as the difference between the two weights recorded by capacitive transducer 24.

Obviously, the above operating sequence relative to container 15 is repeated for container 16.

It should be pointed out that each piston 27 may be locked selectively in the closed position, preventing product feed along chute 26 into chamber 21, when pocket 14 contains no bottom shell 2, or when only one product is to be fed into bottom shell 2 and its weight checked by an auxiliary weighing device off wheel 3.

With reference to FIGS. 2 and 3 e, pistons 27 are locked selectively into position closing respective chutes 26 by a lock device 45 comprising, at each container 15, 16, a respective actuating cylinder 46, which is fixed to frame 5, beneath metering devices 18, has a longitudinal axis 47 parallel to direction 17 and offset radially with respect to axes 20, and supports a substantially flat cam 48 fitted to the output rod of cylinder 46 and perpendicular to axis 47.

Device 45 also comprises, for each device 18, a respective crank 49 hinged to disk 7 to rotate, with respect to disk 7, about a hinge axis 50 substantially parallel to direction 17.

Cylinder 46 moves cam 48 in direction 17 between a lowered rest position, in which cam 48 is positioned clear of the path of cranks 49 about axis 4, and a raised work position, in which cam 48 is positioned along the path of cranks 49 to intercept and move crank 49 of relative device 18 into a work position (shown in FIG. 3 e and by the dash line in FIG. 2) in which crank 49 is positioned beneath piston 27 to prevent it being lowered into position to open chute 26.

Crank 49 is moved from the work position to a rest position—shown by the dash line in FIG. 3 e, and in which crank 49 releases piston 27—by a return spring (not shown) and by a further cam (not shown) identical to cam 48.

In connection with the above, it should be pointed out that the upward thrust exerted by spring 34 on top sleeve 32 is less than the downward thrust exerted by cam 30 on follower roller 31, and therefore on sleeve 32, when piston 27 is locked in the closed position, thus enabling sleeve 32 to move down in opposition to spring 34, and piston 27 to remain stationary in direction 17.

Machine 1 has several advantages, mainly due to transfer chamber 21, i.e. an intermediate chamber between metering chamber 19 and bottom shell 2, which allows metering device 18 to fill chamber 19 correctly with each product, and weighing device 25 to correctly weigh the portion of shutter 36 projecting inside chamber 21, and the product inside chamber 21. 

1) A machine for filling capsules or similar with at least two products, in particular pharmaceutical products in granules; each capsule comprising a bottom shell (2), and a top shell closing the bottom shell (2); the machine comprising conveying means (11) for feeding each bottom shell (2) continuously along a given path (P); at least two tanks (15, 16) containing respective products; at least one metering wheel (3) mounted to rotate continuously about a respective substantially vertical axis (4); and a number of metering devices (18), each of which is fed by the metering wheel (3) along a portion of the path (P), in time with a respective bottom shell (2), to feed the products into the bottom shell (2), and comprises a metering chamber (19) for receiving a given quantity of product from each tank (15, 16); and the machine being characterized by each metering device (18) also comprising a transfer chamber (21), which receives and transfers the product from the relative metering chamber (19), and comprises a weighing device (25) for weighing the product in the transfer chamber (21). 2) A machine as claimed in claim 1, wherein the weighing device (25) comprises at least one capacitive transducer (24). 3) A machine as claimed in claim 1, wherein the weighing device (25) comprises a bushing (23) forming at least part of said transfer chamber (21). 4) A machine as claimed in claim 3, wherein the bushing (23) comprises at least one capacitive transducer (24). 5) A machine as claimed in claim 1, wherein each metering device (18) also comprises a feed chute (26) for feeding the products from the metering chamber (19) to the transfer chamber (21); and a piston (27), which defines the bottom of the metering chamber (19), and is movable, along the metering chamber (19) and parallel to said axis (4), between an open position and a closed position opening and closing the feed chute (26) respectively. 6) A machine as claimed in claim 5, and also comprising first actuating means (29) for moving the pistons (27) to and from their respective said open positions; the first actuating means (29) comprising a first cam (30) extending about said axis (4), and, for each piston (27), at least one first cam follower (31) fitted to the piston (27) and engaging the first cam (30). 7) A machine as claimed in claim 5, and also comprising a lock device (45) for selectively locking each piston (27) in the closed position. 8) A machine as claimed in claim 7, wherein, for each metering device (18), the lock device (45) comprises a respective lock member (49) movable between a lock position locking the relative piston (27) in the closed position, and a release position. 9) A machine as claimed in claim 8, wherein each first cam follower (31) is fitted slidably to the relative piston (27); a retaining device (34, 35) being provided to secure the first cam follower (31) axially on the piston (27) when the lock member (49) is in the release position. 10) A machine as claimed in claim 9, wherein the retaining device (34, 35) is designed to secure the first cam follower (31) axially on the piston (27) with less force than that exerted by the first cam (30) on the first cam follower (31) when the lock member (49) is in the lock position. 11) A machine as claimed in claim 1, wherein each metering device (18) also comprises a shutter (36), which defines the bottom of the transfer chamber (21), and is movable between an open position and a closed position opening and closing the transfer chamber (21) respectively. 12) A machine as claimed in claim 11, and also comprising second actuating means (39) for moving the shutters (36) between said open and closed positions; the second actuating means (39) comprising a second cam (39) engaged by the shutters (36). 13) A machine as claimed in claim 11, wherein the shutter (36) is substantially L-shaped, and comprises a stopper plate (42), and a supporting rod (40) supporting the stopper plate (42); the supporting rod (40) being substantially parallel to and offset with respect to a longitudinal axis (22) of the transfer chamber (21), and having a wedge-shaped portion (41) for dislodging any product clogging the transfer chamber (21). 14) A method of filling capsules or similar with at least two products, in particular pharmaceutical products in granules, on a machine comprising at least two tanks (15, 16) containing respective products; and at least one metering wheel (3) mounted to rotate continuously about a respective substantially vertical longitudinal axis (4), and having a number of metering devices (18); each capsule comprising a bottom shell (2), and a top shell closing the bottom shell (2); and the method comprising the steps of: feeding the bottom shells (2) continuously along a given path (P); feeding each metering device (18) along a portion of the path (P), in time with a respective bottom shell (2); and transferring a given quantity of each product from the relative tank (15, 16) to a metering chamber (19) of the metering device (18); the method being characterized by also comprising the steps of: transferring the product from the metering chamber (19) to a transfer chamber (21) of the metering device (18); weighing the product in the transfer chamber (21) inside the transfer chamber (21) itself; and transferring the product from the transfer chamber (21) into the relative bottom shell (2). 15) A method as claimed in claim 14, wherein the product in each transfer chamber (21) is weighed by means of at least one capacitive transducer (24). 16) A method as claimed in claim 14, wherein the product in each transfer chamber (21) is weighed inside a bushing (23) at least partly defining the transfer chamber (21). 17) A method as claimed in claim 16, wherein the bushing (23) comprises at least one capacitive transducer (24). 18) A method as claimed in claim 14, wherein the metering chamber (19) of each metering device (18) is closed at the bottom by a piston (27); the method also comprising the step of moving the piston (27) between a closed position, in which the metering chamber (19) is separated from the transfer (21), and an open position, in which the metering chamber (19) is connected to the transfer chamber (21). 19) A method as claimed in claim 18, and also comprising the step of selectively locking each piston (27) in the closed position. 20) A method as claimed in claim 14, wherein the transfer chamber (21) of each metering device (18) is closed at the bottom by a respective shutter (36); the method also comprising the step of moving the shutter (36) between a closed position, in which the transfer chamber (21) is separated from the relative bottom shell (2), and an open position, in which the transfer chamber (21) communicates with the relative bottom shell (2). 